Terminal for resistors



Nov. 3, l93L M, BJORNDAL 1,830,084

I TERMINAL FOR RESISTORS Filed Oct. 28, 1929 l N v EN TQ R MA GA/us BJoeNDA/z.

ATT EY Patented Nov. `3,-1931 UNITED 'STATES PATENT OFFICE MAGNUS BJORNDAL, or JERSEY CITY,- NEW JERSEY, AssIGNoR 'ro HARDWICK, HINDLE,

Inc., or NEWARK, NEW JERSEY, a CORPORATION or NEW JERSEY 'DIERENAL FOR RESISTORS This invention relates to contacts or terminals for resistance units of the type consisting of a tubular member upon which is wound a wire of suitable resistance embedded @in vitreous enamel or other suitable insulating material.

Inthe manufacture of such resistors the method of making contact between the ends of the wire'and the terminals by which it is connected in circuit is of the utmost importance in order that the resistance at the points of attachment of the wire may be reduced to a minimum and all danger of the enamel iiowing between the wire and the terminal during j the coating process be eliminated.

Y Methods of attaching the wire that require the latter to be bent sharply about any parts of thel terminal are objectionable on account of the relatively small area of contact which means relatively high" resistance at these points with consequent generation of heat when current lflows through the resistor. This heat in addition to that generated in the wire by the currentmay be enough to slowly oxidize and. corrode the contact to a point where an open circuit will occur. More especially is this likely to happen in the case of resistors designed to carryvcurrents of rela-. tively large magnitude. yIt is an object of this invention to provide aterminal particularlyA adapted for use i11- resistorsdesigned to carry relatively heavy currents, or heavy duty resistors as they are usually called, and which may bel easily and 36 cheaply lmanufactured and assembled with the other `parts of the resistor.

Inaccordance with the invention the terminal consists o f -a conducting strip adapted to be bent aroundl the tubular member of the resistor and fastenedin place thereon by a.l staple or other suitable device. The end of the wireis'wound yabout the extended .con-V The particular nature of the invention as well as other objects and advantages thereof will appear most clearly from a description of a preferred embodiment as shown in the accompanying drawings in which Fig. 1 is a slde view of a reslstor showing one of the terminals in completed form and the other one with the lug detached from the strip, as it is preparatory to being applied thereto,

Fig. 2 is an end view of the resistor showing the appearance of the strip before the lug is applied,

. Fig. 3 is a view of the strip as initially formed,

Fig. 4 is a sectional view through the terminal taken along the line 4-4 o Fig. 1,

Fig. -5 is a similar'view taken along the line 5-5 of Fig. 1, and

Fig. 6 is a view of the lug as initially formed.

The resistor consists of a tubular member l of suitable insulating material upon which is wound a wire 2 of suitable resistance and. y

current carrying capacity. The terminal consists of a strip 3 of conducting material, sueh as copper, provided with a tab J4 adapted when the strip is bent around the end of the member 1 to fit within a recess 5 inthe end of the member to prevent the strip from turning thereon. The strip is clamped about the tubular member by a staple 6 bent about the extended ends of the strip to hold them in contact as shown mostclearl in Fig. 4l

As shown most clearly at tlie right-hand end of Fig. 1 and in Fig. `2 an end of the -wire 2'is wound several times about .theextended ends of the strip above the staple 6. A lug -7 is initially formed with a U-shaped base 8 and a ring portion 9 as shown in Fig. 6. As shown in dotted llines in this figure and in cross section in Fig. 5 the .prongs of the base' are bent around the wire on the extended ends of the strip and pressed tightly against the wire tc provide good electrical contact f between-these arts. To further. secure the lug firmly in p ace it may be indented as indicated at 10. It may also be welded or otherwise attached to the wire vto form a good 'electrical contact.. Y. f

i The final operation in the manufacture of the resistor is the coating of the tubular member 1, the wire 2, the bent portions of the strips 3 and the bases 8 of the lugs by suitable 'material, such. as vitreous enamel, leaving the ringsl9 of the lugs exposed for attachment to suitablefastening devices ofthe apparatus in which the resistor is to be used and for the purpose of permitting external wires t'o be p '1 soldered: or otherwise connectedv theretoz -While a preferredV embodiment ofA the in-V vention has been shown and described herein, it will be understood that variouschanges in the details of construction may be made without departing fromv the` principle of the invention as dened in the appended' claims.

I claim: A 1'. A terminal for a resistor of the type having 'a' member u onwhich a'wire is wound, 2 consistingof a1 strip of conducting material n bent aroundV the member, means for .holding the st'rip in place on the member with a portion projecting therefrom to lprovide an extension about which an end of the wire is wound, and a lug having a base fitting tightly about the wire on the extension and a portion for 'connection to an external circuit.

2. A terminal'for a resistor of the type having afmember upon which a wire is wou-nd consisting of a strip of conducting material bent around the member, means for holding the-strip in place on the member with a portion projecting therefrom to provide an extension about which'a'n end of the wire is wound, anda lug having a base formed of prongs which it tightly around the wire 'on the extension and a portion for connection to an external circuit. Y v

In testimony whereof I aix my signature.

MAGNUS BJORNDAL 

